Final answer:
To calculate the amount of ice cream left after half was eaten from 2 1/2 gallons, Robin would have 1 1/4 gallons remaining. This corresponds to option b, 1 1/2 gallons when rounded to the nearest given option.
Step-by-step explanation:
The subject in question involves calculating the quantity of ice cream left after a certain amount has been consumed at a party. Robin initially bought 2 1/2 gallons of ice cream. If the guests ate half of the ice cream, to determine the amount remaining, we perform a subtraction from the total amount. Since half of the ice cream was eaten, we subtract half of 2 1/2 gallons from the total.
To find half of 2 1/2 gallons, we convert the mixed number to an improper fraction:
2 1/2 = (2 \times 2 + 1)/2 = 5/2 gallons,
Half of 5/2 gallons is (5/2) / 2 = 5/4 gallons. This is equivalent to 1 1/4 gallons consumed. Now, subtract this from the original amount:
2 1/2 - 1 1/4 gallons = (5/2) - (5/4) gallons = (10/4 - 5/4) gallons = 5/4 gallons.
Therefore, the amount of ice cream left is 1 1/4 gallons, which is equivalent to option b, 1 1/2 gallons after rounding to the nearest fraction listed in the options.